Related websites

Light Trap Data

​​​Devonport (Stony Rise) light trap data

The spreadsheets below contain weekly counts for 13 pests and three beneficial insects caught in a 160 watt mercury vapor Rothamsted-design light trap located at Stony Rise near Devonport.

It provides an indication of the flight activity of these pests comparing the current season with average counts for preceding seasons back to 1992 at one Tasmanian location. It is only a broad guide and should not be relied on for specific localities.

Only direct crop monitoring will provide an accurate indication of the activity of caterpillars and their predators in any particular crop.

Several pests migrate into Tasmania every spring from various parts of mainland Australia although some of them (southern armyworm, diamondback moth) also have small populations overwintering in Tasmania. Some pests migrate to Tasmania frequently but never seem to establish breeding populations (cabbage centre grub and green mirid). We would value any reports of the immature stages of these two pests in Tasmania.​

The reliability of forecasting outbreaks of caterpillars of these pests based on influxes of the parent adult moths has not been rigorously tested for most of the species. However, for southern armyworm, it was found through several decades of experience that the moth catches in outbreak years exceed average catches by an order of magnitude but sometimes accompanied by significant difference across regions of Tasmania.

Further Reference:

A history of forecasting outbreaks of the southern armyworm, Persectania ewingii (Lepidoptera: Noctuidae) in Tasmania.

After a moth lays an egg it can take 1-4 weeks to hatch depending on the amount of ambient heat, which increases as spring progresses. Hence eggs laid in early spring may take 3-4 weeks to hatch whereas eggs laid in summer may hatch less than a week after being laid. The chart shown here below for eggs of native budworm is based on field observations on the mild north-west coast in 1989-90. It can be broadly extrapolated to southern armyworm and cutworms but eggs of diamondback moth will hatch faster. See worksheet Egg Duration for details.